Register control of coin return



J. W. DEHN lREGISTER CONTROL OF' COIN RETURN Nov. 4, 1952 Filed Oct. 29. 1948 Nov. 4, 1952 y J. w. DEHN 2,516,974

REGISTER CONTROL oF coIN RETURN Filed oct. 29. 1948 15 sheets-sheet 2 k al L:

A TTORNEV l J. w. DEHN 2,616,974

REGISTER CONTROL OF COIN RETURN 13 Sheets-Sheet 55 J. W, DE/-N Nov. 4, 1952 Filed octyze, 1948 NOV. 4, 19.52 J, w, DEHN 2,616,974

REGISTER CONTROL OF COIN RETURN Filed Oct. 29. 1948 l5 Sheets-Sheet 4 ro TRAPP/c Esa. ccr

/NvE/v To@ J W DEHN NNN WNW 13 Sheets-Sheet 5 /Nl/ENTOR J l'/.DEHN BY ATTORNEY \\N mdk. NNN.

l J. w. DEHN REGISTER CONTROL oF com RETURN Nov. 4, 1952 Filed oct. 29. V1948 Nov. 4, 1952 -W, DEHN` f 2,616,974

REGISTER CONTROL OF' COIN RETURN /NVE/v TOR J; W DEHN BY @a M ATTORNEY Nov. 4, 1952 J. w. Dl-:HN 2,616,974

REGIIIS'I'EIRl CONTROL 0F' COIN RETURN Filed oct. 29, 194e 1s sheets-sheet 7 /N VEN TOR J. W DE HN 'BY 694W.

ATTORNEY Nov. 4, 1952 J. w. DEHN 2,615,974

REGISTER CONTROL OF' COIN RETURN Filed Oct. 29, 1948 l5 Sheets-Sheet 8 //v VE/v To@ J W DE HN ATTORNEY Nov. 4, 1952 .1. w. DEHN 2,616,974

REGISTER CONTROL oF com RETURN Filed oct. 29,1948 i 15 sheets-sheet 1o Nov. 4, 1952 Jgw. DEHN 2,616,974

REGISTER CONTROL 0F COIN RETURN y 1 3 Sheets-Sheet l1 Filed Oct. 29, 1948 /NvE/vroR J W DEHN BY A @HRM

,ATTORNEY Nov. 4, 1952 J. w. DEHN REGISTER CONTROL oF com RETURN 15 Sheets-Sheet 12 Filed Oct. 29. 1948 mam. WR. NR. QQ@

/Nl/ENTOP J. WDEHN A TTQRNEY Nov. 4, 1952 J. w. DEHN Y REGISTER CONTROL oF coIN RETURN 13 Sheets-Sheet l5 Filed Oct. 29, 1948 E mom\\ /NVE/vrof? J. W. DEHN Arm/:wn

Patented Nov. 4, 1952 REGISTER CONTROL oF coIN RETURN Joseph W.'Dehn, Great Neck, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New

York, N. Y., a corporation of New York Application October 29, 1948, Serial No. 57,398

25 Claims. (Cl. 179-63) This invention relates to telephone systems in which connections between subscriber lines are established by automatic switching equipment and more particularly tor a register circuit which is arranged to test for a coin deposited in the coin box of a pay station line Ato initiate a call and to return such coin if the subscriber dials the connection to an operators position or dials the connection to a line for which free service should be given.

The invention is specifically applicable to a system of the'cross bar type such as is disclosed in Patent No. 2,585,904 granted to A. J. Busch, February 19, 1952.

In a system of this type when a subscriber originates a call, a marker is associated with his line over a marker-connector and in responding to the call establishes a connection from the calling line through the primary and secondary cross bar switches of the line-link frame on which the calling line terminates and the primary and secondary switches of a trunk-link frame to an idle dial pulse originating register circuit. Each register has a tip, ring and sleeve appearance on a trunk-link frame just as a trunk does and the operation of selecting a register and connecting a calling line to it is the same as selecting a trunk and connecting a line to it. These selecting functions, as carried out by the marker, have been described in Patent 2,573,569 to R. E'. Hersey granted October 30, 1951. `This connection between the calling line and register is called the dial tone connection and gets its name from the fact that dial tone is supplied to the calling line over this connection when the register is ready to receive dial pulses.

While the marker is in the process of estab- Alishing this dial tone connection, it records Amarker informs the register if the calling line is a coin line, as will be assumed in the present case, a two-party message rate line or a manual line. In each of these cases the register is required to take action peculiar to that type of call. It is the object of the present invention to provide facilities in the register to take actionY with respect to calls originating on lines of the coin box type.

To attain this object the register, after being informed by the marker that the rcall on which it has been seized is from a coin box line, proceeds to transmit a dial tone to the calling line. After the subscriber has dialed the digits of the desired connection, the register proceeds to make a coin test, except on calls to a zero operator, in which case a coin may not be deposited. If the coin has been deposited, the register-will engage a marker and the call willbe completed.

If ten pulses are dialed for the rst digit and registered by the A digit register, a relay will be operated indicative of the fact that the subscriber has dialed for a connection to a zero operator and that no further dialing should be expected. If a i-lrst digit is dialed followed by a second digit 1 and a third digit 1 commonly known as an X11 code for a connection to a service operator, the register will cause a marker to be called in on the connection. If a 11X code is called, that is two preliminary pulses followed by a series of digit impulses, the register will recognize the code as a call to a service operator or as a directing code and will call in a marker. In all of these cases the register will recognize that further dialing is not to be expected. On zero operator, X11 and 11X calls the originating register returns the coin before calling in the marker.

When dialing is completed and the register has engaged a marker, the marker is informed that the call is of the coin class and the marker then proceeds to establish a connection between the subscriber line and a trunk arranged for coin operation. Such a trunk may be arranged to serve calls of only the coin class or it may be a universal trunk which is arranged for iiat rate, coin and automatic message accounting service.

The register may also return the coin when directed to do so by the marker. Such a call would be one to a free code whose trunks are not arranged for coin operation, other than X11 service operator calls. Since the register does not recognize the need for coin return from the oiiice code it engages a marker in the normal manner. The marker determines from the office code that the subscriber should not be charged, requests the register to make coin return and then releases. The regis er makes coin return and reengages a marker for the completion of the call. If the call is abandoned before the register calls in a marker the register returns the coin.

If the call is abandoned after the register engages the markery for establishing a talking connection with a:.trunk, but before the charge condition has been set, coin return is accomplished by the trunk circuit connecting itself to a coin.

supervisory circuit through a,..coin supervisory link.

If a permanent signal conditionvarises'thedeposited coin is returned before; the ymarker-:is:20

now been set forth, it is believed that a .clearercomprehension of the invention may be secured from -the following-detailed description when read :inconnection withtheiaccompanying drawing'. in which:

Figs-,Lto-9,-inclusive,and1iigs. ll and 12 show portionsfof a dial pulse originating register', Fig. 10shows portions-of a marker-.connector Yand a marker, Fig. 13 shows schematically.asubscriber -line ofthe coinV boxtype, a line-linkffrarne'on which thexsubscriber line appears, a line-link connectoL-a trunk-link frame onwhich an voriginating sender terminates, aV trunk-link connector fand'line-link--markerconnector', and Fig. ,14 -i s. adiagramv showing -how theotherngures -oi the :drawing -should bevarranged for V'a Acomplete disclosureaof the invention.

.Ofqthe figures ofthe drawingabove enumerated Whichoisclose the originating register, Fig. l shows-fthe coin testrelays and related circuits;

Fig.- 2 shows the coin return relays and related circuits;

Fig: 3-shows the Adigit translator;

Fig. vi shows the register'ltiming*circuit;v

Fig. `5sl'1owsaapo1tion of `the register Acontrol relays-and circuits;

Figflin the left portion thereof showsthe prefix counter and -X11 code relays vand in the right portion thereof ftwo of the dial pulse registers; Y Fig. 7';showsin the fright portion thereof the "delay timing circuitand in the left'portion thereof :the marker selection circuit;

' Fig. `8 shows Ainthe right;portionthereofa vpart of-xthe dial pulse-countingcircuits andin the -left.portionfthereof-the remainder of .the register control relays and circuits;

Fig.` 9 shows v.others of the dial pulse Vregisters; Fig. 1l shows the remaindenoffthe-dial pulse counting circuit; and

Fig. 12 shows additional relays andcircuits of the dial pulse registers.

The .circuits and apparatus schematically Aindicated in-'the `drawings are fully disclosed and Adescribedin the patent -to A. J. Busch,-herein Ybefore referred to and such portionsY of said lvpatent as are of jassistance in -the comprehension of the present invention are tor-be considered as incorporated herein, by reference, to the :saine :extent asV though set forth in-detail.

' `'lheginvention having been set forth ina genfceralmannerwill now be considered vin detail. It `willrbe.. assumed that the subscriberat the sub- 75 `:mar-ker preferentially-selectsona station |300 of a coin box line initiates a call by removing his receiver from the switchbook whereupon a connection is established from the line-link frame on which the calling line terminates to an idle marker, for example the marker disclosed in part in Fig. 10. Access to the marker is gained through the line-link marker connector |302 which connects only such leads over cable |303 as are necessary to identify the line-link frame to the marker by its frame number and to inform the marker that a dialing connection is to be established. The marker then' proceeds through its trunk Aand register selection control V'circuits `105i() to select an idle originating register.

Originating registers are distributed over the .trunk-ilinkiframes., By means of test leads extendingfrom the-registers through the trunk- ,link fra-mes to the fmarker, the marker deter- ;imi-nes whichltrunkalink frames have idle registers and :which .framesare not being used by other markers. It then .preferentially selects an idle frame withl idle-registers and connects to the framegthrough the trunk-link connector. The marker then preferentially selects an idle register andconnects to it. Theseselection and connection functions ,areperformed in theinanner disclosed in the patent to..R. E. .Hersey hereinbefore referredto. It willbe `assumed that theoriginating register .disclosed in part in Figs. y1 to .9, inclusive, and Figs..11and.12-.is idleandis accessible from .the idle .trunk-.link frame 304 which isconnected Vto the marker through the trunklink frame connector |305.

The location of the calling line-is l.begun as soon as Vthe markeris seized andcontinues while vthe marker is selecting ,an idle register. Line location -is madeinterms of the line-,link frame, the vertical group, the horizontal` groupand the vvertical file. The line-link verticalgroup of subscribers linesis five verticals wide .and ten switches high. Following ,marker seizurethe marker determines which `vertical group .contains Ythe line awaiting service. The vertical group contains `a maximum of .-ftysubscribers lines, therefore the-.determinationof the'vertical .group .localizes thesubscriberline Yas within fifty of ,a maximum of sixhundredand ninety lines terminating on .the frame.

Theline-link .horizontal .group of subscsiber lines isone .switch -high vand vthe width of the supplied vline of switches, the maximum width being thatof a framecontainingfourteen verticalgroups. Themarker determines whichhorizontal group has .one ormore lines within the selected vertical Vgroup awaiting service and the ,marker then preferentially selects one group.

Theline to be servedhas now been vlocated within .five .lines `as-determined by the selected vertical .and horizontal groups.

Line locationdoes not proceed past the horizontal group selection until themarkerhas seized the trunk-link frame. Following trunk-link frame seizure the marker seizes the line-link vframe |306 which has identified itself through its marker connector |302 whereby leads, are eX- ,tended to the marker for vertical .file identication and forcompleting connections to theframe The line-link Vertical file of subscribers lines is onefvertical wide .and-tenswitches high. Thus one Vertical group containsve vertical les.

The markertests theve lines found in the verti- `cal group in which thecallingline is'located and .if morevvthanfone line Aare awaitingnservice the The marker then transmits the line-link frame number and the 'selected line location to the originating register.

After the horizontal group has been determined and an originating register seized, the marker selects one of ten channels which may be used to connect the calling line to the register. The marker tests the junctor, line link and trunk link in each channel to see what junctors or links are already in use on other calls. The lowest numbered available channel is chosen and the marker operates the select and hold magnets on the line-link and trunk-link frames to establish the channel. It is assumed that the selected channel extends over the line-link frame |306 and the trunk-link frame |304. When the channel is selected the marker indicates to the register the number of the line link used in the channel and the register stores this information for future use.

It will be assumed that the marker has become associated with the originating register disclosed in part herein and that the register is idle as will be indicated by the unoperated condition of the ON relay 500. Therefore, battery at the marker through the winding of a trunk test relayV will be applied through the trunk-link frame connector to conductor 50| and ground will be applied through the connector to conductor 502 thereby completing a circuit from battery on conductor 50| through the winding of the F relay 503, over the upper No. back contact of the ON relay 500, conductor 504, the upper No. 3 normal contacts of the PD relay 420, the upper No. 3 back contact of the TM| relay 42|,` conductor 505, the upper No. 1 back contact of the MB relay 508 and over conductor 502 to ground at the marker. Relay 503 thereupon operates and locks over its upper No. l contact to ground on conductor 502 so that its continued operation is dependent entirely upon the marker, and establishes a circuit from ground at the marker, over conductor 501 and its upper No. 3 contacts through the winding of the SI relay 508 to battery. Relay 508 operates and over its lower No. 3 contacts establishes an obvious circuit for the ON relay 500.

The S| relay 508 at its lower No. 2 contacts and the ON relay 500 at its upper No. 4 contacts connect ground to the off-normal ground conductor 500 thereby establishing a circuit through the middle biasing winding of the L relay 800 and through resistor 80| to battery whereby the armature of this polarized relay is biased against its left contact. The connection of ground to conductor 509 is also effective vto establish a circuit over the No. l back contact of the RA relay 802 and through the winding of the RAI relay 803 to battery whereupon relay 803 operates. The ON relay 500 also connects ground over its lower No. 3 contacts and conductor 5|0 to the armature of the L relay 800, but with such armature biased against its left or back contact, the connection of such ground cannot be effective to establish the operating circuit through the Winding of the LA relay 804 and the Winding of the SR relay 805 which if operated might generate a false pulse.

The ON relay 500 at its upper No. 5 back contact opens the initial operating circuit for the F relay 503 but as previously stated, relay 503 upon operating has locked itself under the control of the marker.

The ON relay 500 upon operating also initiates the operation of the register timing circuit of Fig. 4 by connecting ground over its upper No. 2 contacts to conductor 5|| thereby establishing a circuit over the lower back contact of the TMB relay 400 and through the upper winding of the TMA relay 40| to battery. Relay 40| thereupon operates and establishes a looking circuit for itself from battery through its lower winding and inner lower contacts'and an operating circuit from battery through the winding of relay 400, thence over its lower contacts, conductor 402, the lower No. l back contact of the CNTI relay |00, conductor |0I, over the upper No. 3 back contact of the CRA relay 200, conductor 20|, the upper No. 2 contacts of operated relay 803, conductor 800 and in parallel with the contacts of relay 803 from conductor 20|, over conductor 5|2, the lower No. 3 back contact of the PD relay 420 and conductor 403 to conductor 800, and thence over the upper normal contacts of the MST relay to ground on conductor 5||. Relay 400 thereupon operates and its lower back contact opens the initial operating circuit of relay 40|. Relay 40| upon operating opens at its upper back contact the discharge path for condenser 403 through resistor 405, and at its upper front contact es tablishes a charging path for condenser 404 extending from the source 406 of positive potential, V

through resistor 401, over the back contact of the OVL relay 408, through resistor 405, condenser 404, over the upper front contact of relay 40| and to ground through the winding of the TM relay 409. The condenser 404 charges in this circuit at a rate determined by the value of resistors 405 and 401 until it becomes charged, at which time the positive potential applied from the source 405 through resistors 401, 405 and 410 to the control cathode 4|| of tube 4|2, will reach such a value that the tube will break down across its control gap between cathodes lill and 4|3, whereupon the TM relay 40S will operate in a path from the source 406, across the main gap of the tube between the cathode M3 and the anode 4|4, over the upper front contact of relay 40| and to ground through the winding of relay 400. Relay 409 is thus operated a timed interval following the operation of relay 40| for a purpose to be later described unless the holding circuit for relay 40| is opened before the completion of the timing cycle. opened and relay 40| releases, it opens the charging path of condenser 404 at its upper front contact and at its upper back contact closes the discharge path for the condenser. elay 408 which starts its release at the time the locking circuit of relay 40| is opened is made suiiiciently Islow to release so that it will not reclose the initial operating circuit of relay 400 until the condenser 404 has become substantially discharged.

The marker following its seizure by the calling line secures the location of the calling line on a line-link frame and the class of the calling line and in accordance with the information received with respect to the calling line location proceeds to establish a connection between the selected register and calling line over switches of the trunk-link frame and switches on the line-link frame on which the calling line terminates. The marker also proceeds to transmit the class information to the register. Under the assumption made that the calling line is of the coin box class, the marker establishes a circuit from ground over the trunk-link connector circuit, conductor 5|3, the upper No. 5 contacts of the F relay 503, conductor 5|4 and to battery through the winding of the CN relay |02. Relay |02 If the circuit of relay 40| is thus thereupon operates and 'locks over its lower contacts,conductor |02 and 'to' ground over the upper No. 3contactsof the vON relay 5ml; establishesfa biasing .circuit from ground over its inner lower contacts and through the lower biasing winding of the CLR relay |06 and establishes afcircuit from ground .over its inner lower contacts, conductor |55, the lower back rcontact of the LTI relay 236 and to battery through the winding of the CNI relay 255.

The `marker after ytransmitting the necessary information to the register releases the F relay 503 `whereupon the register is disconnected from the common leads of the trunk-link and connector circuit so that the leads may be used for other .calls and the'trunlr-linli frame relayln-ot shown) `which has been operated from' ground over the upper No. 2 contacts of the F relay 555 transfers the tip, ring and-sleeve conductors of the dial tone connection to the corresponding conductors 555, 515 and-5l of the register. The ON'relay 555 'being operated, connects ground over its upper No. 1 Vcontacts and over the upper No.1 back-contact of the RL relay V5i8 through the :low resistance 5|5, to the sleeve conductor 5|? thereby holding the dial tone connection.

A lcircuit is now effective for the L relay 855 which 'may be traced from battery over the upper normal contacts of jack 851, through the upper winding of relay 252, over the lower normal contacts of ljack 557, conductor 852, through the upper lright winding of the dial tone coil 52?, conductor 52 in parallel over the upper Nos. 1 and 2 normal contacts of the CR relay 252, the lower No. l normal contacts of the CRl relay 253, conductor 284, the lower No, 3 back Contact of the CNTl relay l 82, conductor E21, the upper No. 2 back contact of the RL relay 5 i8, over the ring conductor thence over the calling line loop and returning over the tip conductor 5E5, the upper No. 3 baclz'contact of relay 518, conductor |58, the lower No. 2 backccntact of the CNTl relay Mii), conductor 255, the lower No. 2 back contact f the CRI relay 225, conductor 522 and to ground through the lower right winding of dial tone coil 52B.

The current flowing through the upper winding of relay G25 now overcomes the effect of the current flowing through the middle biasing winding and relay 825 operates its armature into engagement with its right or front Contact and, with ground connected to its armature as previously described, completes a circuit extending through the winding of LA relay 852 and the winding of the SR relay 825 to battery. Relay 355 upon operating establishes a circuit over its middle lower contacts and conductor $59, through the winding of the ONl relay 525 to battery whereby suchrelay operates, looks over its upper No. l contacts to ground at the lower back contact of the RL'relay 5i8, supplies off-normal grounds'for the register and over its upper No. 3 contacts estahlishes `a holding circuit 'for the ON relay 552. The Si relay which started to release followthe release of the F relay 523, beingslow to release, does not release to open the circuit of the ON relay 555 before the ON! relay 523 has operated to prepare the holdingr circuit for relay 550.

Relay 523 upon operating establishes a circuit from ground over its lower No. contacts, conductor 526, the lower No. 3 back contact of the 'PZA relay H00, conductor H59 and through the winding vof the AS relay |2l| to battery whereupon relay which is A,the rst of Va groupof 8. sevenwsteering relays which serve to Vcontrol the successive operation of the groups of register relays shown in Figs. 6 and 9, becomes operated. Relay |25| upony operating looks in a circuit over itsflower No. l contacts, the lower No. 3 back contactof the BS relay |202, and conductor 521 to ground over the lower No. '2 contacts of relay 50|).

The SR relay 805 upon operating is also effective to connect the dial tone supply over the inner lower contacts of the PZA relay H00, conductor H5?, the inner lower contacts of relay 805, conductor Bill, the inner lowercontacts -of the MAN relay 524, conductor 525, the upper No, 5 back contact of the ||D relay-'Slifconductor 62|, the lower No. 4 back .contact of the BT relay 10|, conductor |52 `and through the left winding of theldialztone coil 525 to ground whereupon a dialing tone signal istransmtted to the calling line. The subscriber hearing this tone commences to dial the number of the desired connection.

It will first 'beiassumed that he desires a connection to a zero operator and dials the digit O. On the first opening of the line loop, the L relay 855 yreleases thereby opening the circuit previously traced through the 4windings of the LA relay 894 and the SR relay 855. The SR yrelay 805 is slow lreleasing and holds operated during the momentary openings of the right contact of relay 300 but the LA relay S55 follows relay 852, releasing when relay 855 releases and reoperating when 'relay reoperates. The LB relay 8|| in turn follows the LA relay 3mi-its operating circuit extending from battery through its winding, over the front'contact of relay .852, conductor 8 l2, the upper No. 2 contacts of the ON| relay 523 and to ground over the lower No. 3 contacts of the ON relay 555. When the first dial pulse occurs and the LA'relay '865 releaseaa circuit is established from battery through the winding of the RA relay 852 and the back contact of relay 55A to ground on 'conductor SI2 vand relay 822 operates and, being slow to.release,rernains operated during the train or" pulses but will release when relays 800 and 854 remain operated at the end of a train of pulses. When relay B92 operates it supplies holding ground from conductor 5i2, over its lower No.V 4 contacts for the LC relay SiS, LD relay SI5 and LE relay 515. Due to the fact that the RA relay 502 is somewhat slow in operating as well as in releasing, the LB relay is arranged to close this holding circuit over its back contacts until the RA `relay 822 has had time to operate.

The VRAl relay 253, which operated as soon as the register was seized by a marker, provides temporary holding circuits for the Pl to P5 relays Ii to 'l |06, inclusive. When the RA relay 852 operates, relay 355 releases partly closing the operating circuit of the even P2, P5 and P6 relays and closing the locking-circui for all relays Pl to P5, inclusive. With relay^Sil2 operated and relay ses released, the register Yis ready -to count dial pulses. Onfeach closure of the left or back contact of the L relay 355, there is a connection oi ground from conductor 5l2, over such contacts, theupper contacts of the SR relay 805, conductor Slt, the lower No. yl back contact of the MSTI relay i533, conductor 104, and to contacts of the LE relay 8 I5. The first release of the L relay 850 in response to the first pulse therefore completes a circuit over the No. 2 Vback Contact of the LE relay 2|5 andthrough the winding of the LC relay 8|3 to battery. Relay BIS thereupon operates-and locks in a circuit through the lower winding of the LE relay Yll5, the `upper back contact ground on conductor 8| 2. however, operate in this locking circuit because of the LD relay 8| 4, the inner contacts of relay 8I3, the lower contacts of the RA relay 802 to Relay SI5 does not,

until relay 800 reoperates its lower winding is sliunted. When, however, relay 800 reoperates, relay 8I5 operates. On the next release of relay 800 in response to a second dial pulse, ground is again applied to conductor 104 and a circuit is completed over the upper No. 1 contacts and through the upper Winding of the LE relay 8I5 and to battery through the upper winding of the LD relay 8I4 whereupon relay 8I4 operates and relay 8I5 is held operated. Relay 8I4 upon operating opens the holding circuit for the LC relay 8| 3 -extending as traced through the lower wind- -ing of relay 8I5 and relay 8I3 thereupon releases upper winding of relay 8 I4 is opened andrelay 8 I 5 releases but relay 8I4 is maintained operated over Aa locking circuit which extends from battery through its lower winding and over its lower contacts `to the lupper contacts of the LC relay 8I3 so that relay 8I4 will keep the circuit over its upper contacts to the winding of relay 8I3 opened until it has released. On the next or third impulse and the release of the L relay 800, ground applied to conductor 'me is effective to again operate the LC relay 8I3 and the cycle will be repeated. Pulses Nos. 1, 3, 5, 7 and 9 will thus cause the LE relay 8 I 5 to operate and pulses Nos. 2., 4, 6, 8 and 10 will cause relay 8I5 to release.

The first time that the LE relay 8| 5 operates, it establishes a circuit from ground applied from conductor 8I2, over the lower contacts of the RA relay 802 to conductor 8I1, thence over its No. 3 contacts to conductor 8I8 and over the up- .per No. 2 back contact of the P4 relay II04, the upper No. 1 back contact of the P2 relay II02, the upper No. 2 back contact of the P3 relay I I03, the lower No. 2 back contact of the P5 relay I'I05 and through the lower Winding of the PI relay I I| to battery. Relay IIOI thereupon operates and locks in a circuit from battery through its upper winding and over its upper No. 1 contacts, the lower No. 1 normal contacts of relay vI |02, the upper No. l normal contacts of relay H03, the upper No. 1 normal contacts of relay H04, the upper No. 2 normal contacts of relay H05, conductor 8I9 and the lower No. 1 back contact of the RAI relay 803 to ground on conductor 8 I 2.

. When the LE relay 8l5 releases in response to the second pulse, ground is connected from conductor 8II, over its upper back contact and the upper No. 1 back contact of the RAI relay 803 to conductor 820 and with the PI relay IIOI operated a circuit is completed over the lower No. 2 contacts of relay IIOI, through the winding of the P2 relay II02 to battery and in parallel over the upper No. 1 normal contacts and through the winding of the P2A relay IIU to battery. Relay lI02 thereupon operates and locks over its lower No. 1 alternate contacts and as previously traced over the locking circuit to ground on conductor 8I9 and opens the locking circuit of the PI relay IIOI which thereupon re- Relay H00 also operates and locks over its upper No. 1 alternate contacts to ground on conductor 5 I 0. c

. When the LE relay SI5 again operates in response to the third pulse and connects ground jto conductor 8I8, a circuit is completed over the upper No. 2 back contact of the P4 relay II04,

-over the upper No. 1 front contact of relay II02 and tobattery through thewinding of the P3 relay II03. Relay II03 thereupon operates and locks over its upper No. 1 alternate contacts and the locking circuit previously traced to ground on conductor 8I9 and at its upper No. 1 normal contacts opens the locking circuit of the P2 relay I I02 which now releases.

On the fourth pulse when therLE relay 8I5 releases and applies ground to conductor 820, a circuit is established over the lower No. 1 contacts of operated relay II03 and through the winding of the P4 relay I |04 to battery and relay H04 operates and locks over its upper No. 1

'alternate contacts to groundon conductor BIS and at its upper No. 1 normal contacts opens the locking circuit for the P3 relay H03 which now releases.

On the ifth pulse when the LE relay SI5 again operates and connects ground to conductor 8I8, a circuit is established over the No. 2 front contact of relay H04, now operated, and to battery through the winding of the P5 relay II05 and the latter relay thereupon operates, locks over the lower No. 4 back contact of the PI relay IIO| and over its upper No. 2 alternate contacts to ground on conductor BIS and at its upper No. 2 normal contacts opens the locking circuit of the P4 relay I |04 which now releases.

On the sixth pulse when the LE relay 8I5 again releases and connects ground to conductor 820, a circuit is completed over the upper No. 1 contacts of the operated P5 relay H05 to battery through the lower winding of the P6 relay I |00 and the latter relay now operates and locks through its upper winding and over` its upper No. 1 contacts to ground on conductor BIS and over its upper No. 3 contacts establishes an obvious circuit through the winding of the PGA relay II08 to battery and the latter relay then operates. It is to be noted that the operationvof the P6 relay H06 has not caused the release of the P5 relay H05. A

On the seventhl pulse when the LE relay 8I5 again operates and connects ground to conductor 8I8 a circuit is established over the upper No. 2 back contact of relay II04, the upper No. 1 back contact of relay II02, the upper No. 2 back contact of relay H03, the lower No. 2 contacts of relay H05 and to battery through the lower winding of the PI relay IIIJI to battery. Relay IIOI thereupon operates, locks through'its upper winding and over its upper No; 1 contacts,

.the lower No. 1 normal contacts of relay II02,

the upper No. 1 normal contacts of relay H03, the lower No. 3 contacts of relay IIOI, the upper No. 2 contacts of the P6 relay H06 to ground on conductor 8I9, and, at its lower No. 4 contacts, opens the locking circuit of the P5 relay II05 vwhich now releases. rOn the eighth pulse when the LE relay 8| 5 again releases and connects ground to conductor 820,` a 'circuit is established over theclower No. :2 contacts of the PI relay I IOI through the winding .of the P2 relay H02 to battery and lrelay I I02 operates, locks over its lower No. 1 alternate contacts and the locking circuit previously traced to ground on conductor 8I9 and at its lower No. 1 normal contactsopens the locking circuit 'of relay I IOI which now releases. Y

On the ninth Vpulse when the LE relay 8I5 again operates and connects ground to conductor 8I8, a circuit is established over the upper No. 2 back :fame-.924

contact of` relay- Il 04, ythe-upper No., infront contact of. relay ||02 and through the winding of the P3 relay ||04whereupon relay I|04 operates, locks over itsupper.v No. 1 alternate contactsand thenceas previously traced tov ground on conductor 8|9 and at its upper No.A 1` normal contacts opens the lockingcircuit of the P2.re1ay |02 whichnow releases.

On-the tenth pulse whenthe LEfrelay 8 I 5 `again releases and connects ground. to conductor. 820, 4a circuit is established over thelower No. 1 .con-

tacts. of relay` |.|03 and through thewinding of `the P4 relay ||,04 tobattery and relay ||04 operates,.locks over its upper No. 1 alternate contacts and the upper No. 1 normal contacts of Arelay |105 to ground on conductor 8|9 .fand at its upper No. 1 normal contacts opensthe locking circuitofij.l1e .-PV3 relay ||03 whichnow releases. The followingV table showsfthe relays operated after any pulse:

The pulse countwill, of course, s top when the dial reaches its normal position sothat any P relay or relays may remain operated as shown inthe preceding table.

Whenatrainot pulses for a. d-igit ends, the L relay. 8 00` and LA relay 804,V remainbperated and-.the RA relay,y 802 releases thereby causing the-reoperation of theRAI relay 803. Relay 802 at itsVV lower Nos. 2 and 3 contacts. no wY closes .Pathahreughthe .contacts pf. .the PI. to P5. and PGA relays t0. two @Heads .0. I.- 2. 4ans 1 according; :t @the Pattern.. inthe preceding table. The vQpatin of the RAI relay soa aras nwer No. 1 4back,V contact remoyes ground from `conductor 8 9 thereby. releasing .any operatedA P relays, and thereby removingground from. the. two .selected leads. During the operate time of relay 803 and. marcharse.. tmeof the. P..r.e1ays,. a. pair; of the register relays of Figs. 6. and 9 willbeoperated correspondingto the` two leads grounded and corresponding to the digits being registered. 'I fhe leads 0,A 2,` 4 and 'I will be .ex-tended, to the groupsof verelays ofthe registersinsequence, as will be hereinafter described.

When the P2A relay operatedas previously described in response to the second dial pulse, it opened at its, innerV lower back contact the previously traced circuitthrough thepleft winding of the dial tone coil 520 to stopthe transmission of dial tone, opened at its lowermost back contact the initialoperating circuit yof the .AS relay |201 and established the circuit ofxthe EV relay |208 which may be. traced` from battery through thewinding of relay I208,.over. the lower No. 3 back contact of the OD relay |209, the lower No. 3 contactsof the operated AS relay I 20 lfand conductor I2 |0 to ground over the upper No.I 3 contacts of relay H00. Relay |208 connects theg I, 2, 4.and 1 digit leads over'its lower contacts,l thel upper contacts of operated. steering relay I20| and conductors of cable` |2|| to the windings of the relays A0, Al, A2, A4 and A'I of the A digit register 6I0 shownl in Fig. 6. Since the ve leads cannot be connected to the relays of the` A digit register until relay |208 operates following the transmission of two pulses a single pulse digit or series of single; pulse digits will notaffect the A digit register and a Wrong number will not beregistered if the calling subscriber accidentally generates a single pulse byv opening the switchhook contacts before dialing.

Call for zero operator It has been assumed that the callingsubscriber has operated his dial to transmitten pulses since he desires a connection with a zerov operator. Consequently, at the: end of the series of ten pulses, the P4, P8 and PBA pulse counting relays ||04,A ||0|i and ||08 are operated and upon the release ofthe RA relay 802 at the end of pulse series, ground is applied from conductor 509, over the lower No. 3 back contact of relay 802, conductor 82|, the upper No. 3 contacts of the P4 relay H04, the No. 1 front contact of the PSA relay` H08, conductor l, thelower No. 1 contacts of the EV relay |208, the upper No. 1 contacts of the AS relay I20|, aconductor of cable |2|I and through the winding of the A'I relay 6I5 of theA digit register 6|0 to battery, and ground is applied from conductor 509 over; the lower No. 2 back contact. of relay 802, conductor 822, the lower contactsof the P4 relay H04, conductor 4, the lower No.2 contacts of the EV relay |208, the upper No. 2 contacts of the AS relay |,20 aconductor of cable |2|| and through. the windingof the A4 relay-0|4 of the Adigit register 610 to battery. -Relays |4 and`6|5 both operateand lock over` theirupper contacts and conductor 802to ground overv the'lower No. 4 contacts of the ON I relayv523. Thus theV relays of the A digit register 610.1 have. been.operated to register the; digit |0.

Whenthe RA| relay 8.08.0perates atxthe end of the impulse series, ground. -isi removedat its lower-No. 1 back contact. from. conductor 8|9 thereby releasingany operated P relays, in the case assumed, P4,l P6 and PBA relays H04, H06 andg H08, respectively. At itslower No.2 contacts relay. 803 applies ground from conductor -52l, over.conductor. 823,.the upper No. 2 contacts of the. EV relay |208. and the lower No. 2 contacts and winding of the AS relay |20| `to battery for holding the relay |20| operated after the BS relay |202 operates and until the commencement of the counting of the next digit series and at its lower No.` 3. contactsrelay 803` applies ground from conductor 521, over conductory 824, the upper No. 1 contacts of the EV relay |208, thelower No. 5 contacts of the` AS relay I20| and to battery through the winding of the BS relay |202. Relay |202v thereupon operates and locks over its lower No.; 1 contacts and the lower No. 3 back contact ofr the CS relay |203' to ground on conductor 527 preparatory to registering the second digit if dialed. Should a second digit be dialed on a call other than tothe zero operator, the RAI relayy803 releases at the beginning of the second digit series and opens the locking` circuit for the `AS relay |20| and theV initial energizing circuit for the BS relay |202. Relay |20| upon releasing opens the circuit of the EV relay |208 which now releases and with the BSrelay |202 now lockedoperated, a circuit is established from battery through .the winding of lthe OD relay |20 8,

1'3 the upper No. 3 vback contact of relay |208 and to ground over the lower No. contacts ofrelay |202.

At the end of the second digit when the RA! relay v31111 operates, ground applied to conductor 823 is connected over the lower No. 1 contacts of the OD relay |205, the lower No. 2 contacts and through the winding of the BS relay |202 to hold such relay operated when its initial holding circuit is opened by the operation of the CS relay |203 and ground applied to conductor 824 is connected over the lower No. 2 contacts of the OD relay |209, the lower No. 4 contacts of the BS relay |202 and through the winding of the CS relay |203 whereupon relay |203 operates and locks over its lower No. 1 contacts and the lower No. 3 back contact of the DS relay |204 to ground on conductor 521. At the beginning of the third digit series, relay 803 releases and opens the locking circuit for the BS relay |202 and the initial operating circuit for the CS relay |203. Relay |202 upon releasing opens the circuit of the OD relay which now releases and with the CS relay |203 now locked operated, a circuit is established from battery through the winding of the EV relay |200, over the lower No. 3 back contact of the OD relay |200 and to ground over the lower No. 5 contacts of the CS relay |203. This progression continues as each digit is received and it will be noted that with the BS, DS or FS relays |202, |204 ory |206 operated together With the OD relay |209, the leads 0, I, 2, 4 and 'l are extended to the B, D or F digit registers 62 0, 9|0 and 930, respectively, and that with the CS, ES or GS relays |203, |205 or |201 operated together with the EV relay |208, the leads 0, I, 2, 4 and 1 are extended to the C, E and G digit registers 900, 020 or 040, respectively.

In order that the L relay 800 will produce good pulses at its contacts even though the line conditions, dial adjustment and central oiiice voltage have wide variations, corrective devices have been added to the L relay and its associated circuits. The relay is provided with no retractile spring but instead is provided with a middle winding which is energized in the direction to hold the armature against its left or back contact when no current is flowing through its upper or line winding, whereas the line winding is energized in the direction to hold the armature against its right or front contact. This partly compensates for battery Voltage variations and also causes the relay Yto release quickly when the line winding is opened since the releasing force does not decrease as the armature restores to normal as it would if a retractile spring were used. Another advantage of the bias winding is that it causes the armature flux to reverse even though there is a current iiow through the line winding and line leak and thus the relay does not have to release against a residual-flux due to line leak.

A third or lower winding is provided in order to kinsure that the contact closures will not be less than a minimum Value determined by the time constant of the circuit through the lower winding. When the front or right contact of the relay closes in response to the energization of the upper or line winding, condenser 825 charges in a circuit from ground over conductor 5|0, over the front contact of the relay, through the winding of the LA relay 804, through the condenser and the lower winding of the L relay 800 to battery. The charging current is in a direction to vhold the relay operated and the relay will be held operated at least until the condenser becomes suiiiciently charged and the current sulciently reduced so that the magnetizing force of the lower winding becomes less than that of the middle or biasing winding. When the front contact of the relay opens, condenser 825 discharges in a circuit through the lower winding of the relay and through resistor 826. The direction of the discharge current is such that the armature is held against its back contact at least for the time required for the condenser to discharge and reduce the current sufciently so that the sum of the magnetizing forces due to the two lower windings becomes less than the magnetizing force due to the upper or line winding. The lower winding of the relay thus causes the armature to remain on whichever Contact has closed for a time long enough to perform the required functions even though the line conditions or dial adjustment tend to cause very short contact'closures of the relay.

It has been assumed that the subscriber has dialed but one digit zero and therefore when the P4 relay ||04 and the P6 relay ||06 operated to count the ten impulses of this digit and with the AS relay |20| operated a circuit is established from ground on conductor 8|9, over the upper No. 2 normal contacts of the P5 relay |05, the upper No. 1 alternate contacts of the P4 relay H04, the lower No. 1 contacts of the P6 relay |06, conductor i I0, the lower No. 4 contacts of the AS relay |20| conductor |2 I3, the upper No. 2 contacts ofthe ||D relay 600, conductor 603 and to battery through the winding of the OP relay H4. Relay M4 operates over this circuit, locks over its lower contacts to ground on conductor 8 2 and establishes a circuit from ground over its upper contacts, conductor 4 5, the upper No. 3 contacts of the operated CNI relay 206, the upper vNo. 5 back contact of the LT2 relay 201 and to battery through the winding of the CR relay 202.

Relay 202 upon operating establishes a holding circuit for the L relay 800 which may be traced from battery over the upper normal contacts of jack 801, through the upper winding of relay B00, over the lower normal contacts of jack 801, conductor 008, through the upper right winding of dial tone coil 520, conductor 52|, the upper No. '1 alternate contacts of the CR relay 202, through resistance 208, over conductor 209 and to ground over the No.3 contacts of the LB relay 8| At its Nos. 1 and 2 normal contacts relay 202 also disconnects the upper or line winding of the L relay 800 from the ring conductor of the calling line so that the 13G-volt coin return current when connected to the calling line by the operation of the CR! relay 203, as later described, will not be connected to the upper winding of the L relay 800. Relay 202 also establishes the circuit of the MST! relay 103 which circuit extends from battery through the winding of such relay, over conductor 105, the upper No. 4 contacts of relay 202,

conductor 2| 0, the lower No. 1 back contact of the TM relay 409 and to ground on conductor 5||. Relay 103 thereupon operates and opens at its lower No. 4 back contact the circuit previously traced from the front contact of the line relay 800 to prevent further dial pulse registraion.

The CR relay 202 also establishes an obvious circuit over its upper No. 3 contacts for the CRI relay 203 which operates; at its lower No. 2 back contact disconnects the lower right winding of the dial tone coil 520 from the tip conductor of the calling line, and connects 13G-volt coin return battery through resistor 2| over the lower back contact of the CB2 relay 2I2, the Ylower No. 

